code: def test_nans(self):
      A = eye(3, format="lil")
      A[1, 1] = np.nan
      b = np.ones(3)
  
      with suppress_warnings() as sup:
          sup.filter(
              DeprecationWarning, ".*called without specifying.*"
          )
          x, info = gcrotmk(A, b, rtol=0, maxiter=10)
          assert_equal(info, 1)
  
file_path: scipy/scipy/sparse/linalg/_isolve/tests/test_gcrotmk.py
imports: from numpy.testing import assert_, assert_allclose, assert_equal, suppress_warnings
  import numpy
  from numpy import zeros, array, allclose
  from scipy.linalg import norm
  from scipy.sparse import csr_matrix, eye, rand
  from scipy.sparse.linalg._interface import LinearOperator
  from scipy.sparse.linalg import splu
  from scipy.sparse.linalg._isolve import gcrotmk, gmres
label_desc: Use image node_id 4 for calling the TestGCROTMK obj's underlying member method code with example usage: obj.test_nans() without return types